－This is a useful dictionary, I think.

－So it is, and it’s ______ unusual one.

A. the        B. an C. a   D. 不填

---_________ useful dictionary it is!’
--- ‘I think so.’

______useful dictionary for beginners of English! Where did you get it?

    A. How          B. How an           C. What a           D. What an

---_________ useful dictionary it is!’

--- ‘I think so.’

A．how             B．what             C．what a            D．what an